In many cases, treatment of an object or a region formed by the object and the medium surrounding the object, such as water and water systems, is necessary in order for treatment effects to be carried out, such as preventing corrosion, controlling bacteria and biological growth, controlling scale formation, water-hardness softening, and the like.
Water contains many different substances either in compound or ionic forms. These contents are beneficial in some usages but could also create undesirable effects in some applications. For cooling water and boiler water systems, contents such as calcium, silica, carbonates, oxygen etc. may contribute to mineral scaling, corrosion, bacteria issues etc. Commonly, these undesirable issues are controlled by using chemical or physical water treatment methods. However, existing chemical and physical treatment systems available in the market have their shortcomings. They either create undesirable impacts to the environment or are ineffective in all round treatment. One of the objects of this invention is to overcome the treatment deficiencies of both the existing chemical and non-chemical treatment methods without further creating negative impact to the environment, whilst still providing a practical and efficacious system and method that can be implemented in various applications, especially for cooling water and boiler water treatment.
Presently, for closed system such as closed loop cooling water systems, various physical and chemical treatment methods as well as electrolysis methods are employed to obtain the respective treatment effects including scaling, corrosion and biological controls. For example, physical treatment methods include methods of permanent or electromagnet treatment, high voltage electrostatic treatment, and ultraviolet light treatment but they are for scaling or biological control without corrosion control function. The chemical treatment methods are based on chemical reactions, in which chemicals which may be harmful to the environment are used and frequently the products created as a result of the chemical reactions are also environmentally unfriendly. One example of a chemical treatment method is for chemicals such as phosphate-based scale/corrosion inhibitors to be used to keep calcium ions remaining dissolved in water without precipitation and provide a protective product to coat the corrosion anode or cathode sites, in order for the control of scaling and corrosion issues in water.
In view of the above, prior art physical and chemical treatment methods have deficiencies and limitations and these impede their full practical implementation in actual applications. The chemical treatment methods are known to do harm to the environment and physical treatment methods are generally designed for single purpose applications, to solve only one of the many treatment issues with only one treatment effect being achieved. Such methods do not solve all the problems simultaneously unless different physical methods are used together. However, in practice many of them resort to using environmentally unfriendly chemicals to meet all the treatment expectations.
Among the physical methods, some use either direct current (DC) or pure AC time-varying frequency electromagnetic waves for various treatment effects. For the DC current-based methods, only constant DC is applied without the AC alternating wave. For the pure AC time-varying frequency electromagnetic wave-based methods, only the AC alternating wave is applied and will not produce the effects of DC. Even if the DC and AC methods are applied separately at the same time, the result of such a combination is to produce a static DC current and the effects of a pure AC wave.
Moreover, none of these prior art systems and methods solve the problems of algae and Legionella bacteria in the most challenging cooling tower environments which are most conducive for algae and Legionella bacteria growth. Typically, AC electromagnetic treatment can reduce the total bacteria count in the cooling tower if the correct frequency and strength are applied, but not the Legionella bacteria count. This is because Legionella bacteria are not sensitive to an indirect AC electromagnetic “field” treatment although some other bacteria species are more responsive. Onsite treatment results have shown that when treated by inductor coil AC electromagnetic alternating fields without the aid of other disinfection chemicals or devices, total bacteria count can be lowered but the Legionella count remains high. Hence for Legionella control, the use of environmental unfriendly chlorine disinfection methods is needed. In fact the frequency ranges used by some of the AC pulsed electromagnetic field treatment methods may actually promote the growth of Legionella bacteria or some other bacteria species. One of the main reasons for ineffectiveness in bacteria or Legionella bacteria control is due to the field treatment which has no ionic current in the water to produce a direct mechanism to kill the bacteria.
It has been always a challenge to develop alternative technologies for obtaining various treatment effects that are effective and cause no harm to the environment, and that advantageously are also able to achieve the various treatment effects all in one go. Therefore, there is a need for new methods and systems that are capable of simultaneously achieving the various treatment effects, and do not cause harm to the atmosphere, aqueous and soil environments and that do not require storage and disposal of final products and by-products.
The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.